51991771731 has 32 divisors (see below), whose sum is σ = 70855538688. Its totient is φ = 33902668800.

The previous prime is 51991771729. The next prime is 51991771757. The reversal of 51991771731 is 13717719915.

It is not a de Polignac number, because 51991771731 - 2¹ = 51991771729 is a prime.

It is a super-2 number, since 2×51991771731² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (51991771771) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26647806 + ... + 26649756.

It is an arithmetic number, because the mean of its divisors is an integer number (2214235584).

Almost surely, 2^51991771731 is an apocalyptic number.

51991771731 is a deficient number, since it is larger than the sum of its proper divisors (18863766957).

51991771731 is a wasteful number, since it uses less digits than its factorization.

51991771731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2891.

The product of its digits is 416745, while the sum is 51.

The spelling of 51991771731 in words is "fifty-one billion, nine hundred ninety-one million, seven hundred seventy-one thousand, seven hundred thirty-one".